WO2013056550A1

WO2013056550A1 - Peak clipping device and mobile communication system

Info

Publication number: WO2013056550A1
Application number: PCT/CN2012/075603
Authority: WO
Inventors: 邓英; 郭天生
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-10-20
Filing date: 2012-05-16
Publication date: 2013-04-25
Also published as: CN202276359U

Abstract

Provided are a peak clipping device and a mobile communication system. The device includes: a peak value pulse generation module configured to generate a peak value pulse signal according to an input signal and send same to a peak value pulse weighting module; a weighted control signal generation module configured to generate a weight factor control signal according to an acquired modulation manner reference signal or frame synchronization signal and send same to the peak value pulse weighting module; a peak value pulse weighting module configured to weight peak value pulse signals received during different time periods respectively according to the received weight factor control signal and send the weighted peak value pulse signals to a first adder module; and a first adder module configured to overlap the weighted peak value pulse signals onto a peak value signal to be clipped to cancel the peak value signal to be clipped. The above technical solution provided by the present utility model realizes the effect that the peak clipping performance in the system can be improved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of signal processing of communication systems, and in particular to a peak clipping device and a mobile communication system. BACKGROUND OF THE INVENTION With the rapid development of mobile communication, the frequency band of wireless communication becomes more and more crowded, and the frequency band resources become more and more tight. In order to accommodate more communication channels in a limited spectrum range, it is necessary to improve the spectrum efficiency of the existing frequency band. This application of many new broadband digital transmission technologies (such as Orthogonal Frequency Division Multiplexing (OFDM), Wideband Code Division Multiple Access (WCDMA), long-term Evolution (Long-Term Evolution, LTE for short) and high spectral efficiency modulation, Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM), Among them, the quadrature amplitude modulation may include 8QAM, 16QAM, 64QAM, etc., in order to achieve higher spectrum utilization density and wider channel space allocation. These highly efficient digital modulation transmission technologies are almost all non-constant envelopes, and non-constant envelope modulation signals will produce large peak-to-average ratios. With the rapid development of information technology, people are increasingly diversified in business applications. Voice services can no longer meet the needs of applications. It is a necessary trend for wireless communication systems to provide high-speed data services. Therefore, a competitive base station system is not only satisfied with supporting voice services and low-speed data services, but also provides high-speed and high-quality data services. It is an essential element of the next generation communication system, which puts forward higher requirements for medium-frequency RF signal processing. How to perform flexible real-time processing on the signal according to the service scheduling situation and ensure the optimization of system performance, which is proposed for the current traditional peak clipping algorithm. A higher requirement. Mainly reflected in the rapid development and application of data services, making the modulation method no longer a single modulation method, such as Global System for Mobile Communication (GSM) system, Enhanced Data Rate GSM Evolution (Enhanced) Data Rate for GSM Evolution) Signals, Code Division Multiple Access (CDMA) EV-DO signals, HSDPA channels in WCDMA, etc., have emerged to provide efficient and high-quality data service transmission. The characteristics of these signals are all modulated with high coding efficiency (8PSK, 16QAM, etc.). The application of diversified services requires the base station to diversify the service support, so that the modulation of the service time slot can be dynamically adjusted according to the service changes. In the method, for the IF peak clipping algorithm, the demodulation tolerances of different modulation modes are different. The traditional peak clipping algorithm does not consider the mixed application of the signal modulation mode and does not distinguish the characteristics of the channel to uniformly process the signal. In this way, the optimal performance of the algorithm cannot be achieved. For the mixed signal, the peak clipping performance of the low-order modulation method is sacrificed to balance the peak clipping of the high-order modulation method. Performance, this can not play the best performance of peak clipping in the system, the decline in peak performance will affect the efficiency of the system. In view of the above problems in the related art, an effective solution has not yet been proposed. SUMMARY OF THE INVENTION The present invention provides a peak clipping device and a mobile communication system to at least solve the above-described related art problem that the peak performance of the peak in the system cannot be exerted, thereby affecting the efficiency index of the system. According to an aspect of the present invention, a peak clipping apparatus is provided, including: a peak pulse generation module, a weighted control signal generation module, a peak pulse weighting module, and a first adder module, wherein a peak pulse generation module is connected to the peak a pulse weighting module configured to generate a peak pulse signal according to the input signal and send the peak pulse weighting module to the peak pulse weighting module; and a weighted control signal generating module connected to the peak pulse weighting module, configured to generate a weight according to the acquired modulation mode reference signal or the frame synchronization signal The factor control signal is sent to the peak pulse weighting module; the peak pulse weighting module is connected to the first adder module, and is configured to weight the peak pulse signals received in different time segments according to the received weighting factor control signals, and weight the signals The processed peak pulse signal is sent to the first adder module; the first adder module is configured to superimpose the weighted processed peak pulse signal on the peak to be peaked signal, and cancel the peak clipping signal. The peak pulse weighting module includes: a weighting factor gating unit, coupled to the weighting control signal generating module, configured to output the plurality of weighting factors into the weighting unit according to the weighting factor control signal generated by the weighting control signal generating module; The weighting unit is connected to the weighting factor gating unit, and is configured to perform weighting processing on the received peak pulse signals of different time periods according to the weighting factor output by the weighting unit gating unit, and superimpose the weighted processed peak pulse signal to On the peak to be cut signal, the peak clipping signal is cancelled. The above weighting unit is a multiplier. The device further includes: a filter connected between the peak pulse weighting module and the first adder module, configured to filter the peak pulse signal after being weighted by the peak pulse weighting module, and filtering the filtered peak pulse signal Send to the first adder module. The device further includes: a peak search module, connected to the second adder module, configured to send an input signal greater than a preset threshold to the second adder module; the first delay module is coupled to the second adder module, Is configured to delay processing the input signal, and send the delayed input signal to the second adder module; the second adder module is configured to receive the input signal from the peak search module and receive the received signal The delayed input signal from the first delay module is superimposed to generate a peak signal, and the peak signal is sent to the peak pulse generation module. The device further includes: a second delay module, connected to the peak search module, configured to delay the input signal from the peak search module and greater than the preset threshold to generate a peak to be peaked signal, and send the peak to be peaked signal Give the first adder module. According to another aspect of the present invention, there is also provided a mobile communication system comprising: the apparatus described above. Through the utility model, the peak pulse weighting module is used to perform weighting processing on the peak pulse signals received in different time segments, and the weighted processed peak pulse signals are sent to the first adder module, and the technical means for canceling the peak clipping signals is performed. The invention solves the problem that the best performance of the peak clipping in the system can not be exerted in the related art, thereby affecting the efficiency index of the system, and the effect of achieving peak performance in the system to achieve better performance is achieved. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate, FIG. Improperly qualified. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a structure of a peak clipping device according to an embodiment of the present invention; FIG. 2 is a schematic structural view of a peak clipping device according to a preferred embodiment of the present invention; FIG. 4 is a schematic structural view of a peak clipping device in a specific application process according to an embodiment of the present invention; FIG. 5 is a schematic diagram of a CDMA high speed according to an embodiment of the present invention. FIG. 6 is a schematic diagram of a frame structure of a forward signal of a TD-SCDMA system according to an embodiment of the present invention; FIG. 7 is a structure of a peak pulse weighting module according to Embodiment 2 of the present invention; FIG. 8 is a timing diagram of correspondence between weighting factor control signals and weight parameters according to an embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. 1 is a block diagram showing the structure of a peak clipping device according to an embodiment of the present invention. As shown in FIG. 1, the peak clipping device includes: a peak pulse generation module 10, a weighting control signal generation module 12, a peak pulse weighting module 14 and a first adder module 16, wherein the peak pulse generation module 10 is connected to a peak pulse Weighting module 14, configured to generate based on the input signal

(pickup) the peak pulse signal and send it to the peak pulse weighting module; the weighting control signal generating module 12 is connected to the peak pulse weighting module 14, and is configured to generate a weighting factor control signal according to the acquired modulation mode reference signal or frame synchronization signal and send it to The peak pulse weighting module 14 is connected to the first adder module 16 and configured to perform weighting processing on the peak pulse signals received in different time segments according to the received weighting factor control signals, and weighting the processed signals. The peak pulse signal is sent to the first adder module 16; the first adder module 16 is arranged to superimpose the weighted processed peak pulse signal on the peak to be peaked signal, and cancel the peak clipping signal. By the above-mentioned peak clipping device, the peak pulse signal received by the peak pulse weighting module is used to perform weighting processing on the peak pulse signals received in different time periods, and the weighted processed peak pulse signal is sent to the first adder module to cancel the peaking signal. Means, therefore, can solve the problem that the best performance of the peak clipping in the system can not be exerted in the related art, thereby affecting the efficiency index of the system, and the effect of achieving peak performance in the system to achieve better performance is achieved. In a specific embodiment of the present invention, as shown in FIG. 2, the peak pulse weighting module 14 may include the following modules: a weighting factor gating unit 140 connected to the weighting control signal generating module 12, and configured to be weighted according to the weighting The weighting factor control signal generated by the control signal generating module 12 outputs the input plurality of weighting factors to the weighting unit 142; the weighting unit 142 is connected to the weighting factor gating unit 140, and is set to be based on the weighting factor gating unit 140. The weighting factor of the output weights the peak pulse signals received in different time periods, and superimposes the weighted peak pulse signal on the peak signal to be peaked, and cancels the peak clipping signal. Wherein, in a specific application, the weighting unit 142 may be implemented by using a multiplier. In a preferred embodiment of the present invention, in order to better improve the peak clipping performance of the system, as shown in FIG. 2, the peak clipping device may further include: a filter 18 connected to the peak pulse weighting module 14 and the One The adder modules 16 are arranged to filter the peak pulse signal weighted by the peak pulse weighting module 14 and send the filtered peak pulse signal to the first adder module 16. In a specific application, as shown in FIG. 2, the above peak clipping device may further include the following hardware module: a peak search module 20, connected to the second adder module 24, configured to send an input signal greater than a preset threshold to a second adder module 24; the first delay module 22 is connected to the second adder module 24, configured to delay the input signal, and send the delayed signal to the second adder module 24; the second adder The module 24 is configured to superimpose the received input signal from the peak search module 20 and the delayed input signal from the first delay module 22 to generate a peak signal, and send the peak signal to the peak pulse generating module 10 . Preferably, the peak clipping device may further include: a second delay module 26 connected to the peak search module 20, configured to delay the input signal from the peak search module 20 and greater than the preset threshold to generate a peak to be peaked. The signal is sent to the first adder module 16 and the peak to be cut. Since the above-mentioned peak clipping device is generally applied to a communication system in a specific application: Therefore, in a specific embodiment of the present invention, a mobile communication system is further provided, comprising: the device described above. In order to better understand the above embodiments, the following detailed description will be made in conjunction with the preferred embodiments and the accompanying drawings. It should be noted that the peak clipping algorithm used in the current system is mostly based on the peak pulse cancellation algorithm. The peak clipping device is shown in FIG. 3, and includes: a peak search module 20, a first delay module 22, and a second adder. Module 24, second delay module 26, peak pulse generation module 10, filter 18, and first adder module 16. The following embodiments relate to 3G or 4G (third generation wireless communication or fourth generation wireless communication system) communication fields, such as peak clipping processing of systems such as TD-SCDMA, CDMA, WiMax, and LTE. The following embodiments adopt the following principles: The frame synchronization signal provided by the system may be a PP2S synchronization reference signal or a baseband signal time slot modulation mode indication signal, etc., which are determined according to different system defined interfaces, and time-sharing or sub-division is constructed according to the reference signals. A canceling pulse weighted control signal of the time slot, combined with different modulation factors of different time periods, defines different weighting factors, and different weights are applied to the peak pulse to achieve real-time adjustment of the amplitude of the peak pulse, thereby ensuring the mixed modulation mode. The peaking performance of the wireless communication signal is optimized under the same threshold. In order to enable the system to use different modulation modes in different applications of voice services and data services in a timely manner, the peak clipping performance is improved. The system of the time-division weighted peak clipping device has the following characteristics: The time-sharing processing of the peak cancellation of the signal can be performed according to different signal modulation modes; the time-sharing processing of the peak cancellation of the signal can be performed according to different time slots or different channels; A modulation mode indication signal or a frame synchronization reference signal can be provided. Embodiment 1 The time-sharing processing needs to generate a time-sharing weighted control signal according to a modulation mode indication signal or a frame synchronization signal of the system, and can respectively control different weights of peak cancellation pulses (ie, peak pulse signals) for different time periods. The weighting factor is typically in the range of 0 to 1. At present, the peak cancellation pulse algorithm adopted by the industry in the wireless communication system mostly uses a cascade structure to complete the peak clipping processing of the signal, so that the signal peak-to-average ratio is not greatly affected, and the setting of each peak clipping module is different. The weighting factor is used to achieve an optimal configuration of signal demodulation performance. As shown in FIG. 4, the peak clipping device includes: a peak search module 20, a first delay module 22, a second adder module 24, a second delay module 26, a peak pulse generation module 10, a filter 18, and a first adder. Module 16, weighted control signal generation module 12 and peak pulse weighting module 14. With respect to the embodiment shown in FIG. 3, the peak clipping device of the present embodiment adds a weighting control signal generating module 12 and a peak pulse weighting module 14, and based on this, weighting processing of peak canceling pulses received at the same time interval can be performed, thereby improving Peak clipping performance of the system. Specifically, the weighting control signal generating module 12 is configured to generate a time-division weighted control signal (ie, a weighting factor control signal) according to the modulation mode indication signal or the frame synchronization indication signal, and the number and duration of the weighting values corresponding to the time-division weighted control signal. It needs to be defined in combination with the application of each system. When the weighting factor parameter is large, the logic can use the state machine. Each state of the weighted control signal can be defined to correspond to a different weighting factor value. The weighting factor value can be set through the software interface. The pulse weighting module 14 weights the original peak cancellation pulse according to a weighting factor set by the system. FIG. 5 is a structural diagram of a CDMA high speed data service EV-DO signal slot according to Embodiment 1 of the present invention. Since the traffic channel and the MAC channel adopt different modulation modes, the degree of impairment that the peak clipping can tolerate for different modulation signals is different. Therefore, it is desirable to improve the overall demodulation index of the signal while ensuring that the peak-to-average ratio of the system is constant. Therefore, it is necessary to perform time-sharing peak clipping according to the channel, so as to ensure that the demodulation performance for each channel satisfies the system requirements without the peak-to-average ratio index being reduced. Specifically, as shown in FIG. 5, the forward direction of the CDMA high-speed data service EV-DO signal is transmitted in a slot manner. The time slots are divided into active time slots and idle time slots. The power in each active time slot is constant and continuous, and the power in each idle time slot is not constant. In addition, whether the EV-DO signal forward link always depends on the service condition at the time of the active time slot. If the current cell does not have a user to apply for a service, then most of the time slots are idle, and the power performance is non-constant. . Only when the cell is busy, the forward direction is always the active time slot. In this case, the forward power is continuously transmitted and constant, and the signal has one of the biggest features: pilot, MAC, and The service or control channel is framed by time division multiplexing, and the modulation modes of the channels are not identical, and the pilot channel is It is transmitted on the I path by the all '0' symbol. The MAC channel symbol is transmitted on the I/Q path after BPSK or OOK modulation. The service and control channel adopts PSK/8PSK/16QAM modulation. For the intermediate frequency peak clipping, The difference in modulation mode determines the degree of peak-to-average ratio reduction. The signal with the same modulation power and different modulation modes adopts the current traditional peak clipping algorithm. The damage to the MAC channel after peak clipping is too large, resulting in the determination of the traffic channel. In the application of peak clipping threshold, the problem of MAC channel demodulation index exceeding the standard, in order to avoid MAC channel damage is too large, it is necessary to increase the peak clipping threshold, which will cause the peak-to-average ratio of the power amplifier signal to rise, which is not conducive to the efficiency of the power amplifier. The peak clipping device of the embodiment performs time-division weighting processing on the peak pulse, and the data of the MAC channel occupies a shorter data of the entire time slot, and the MAC channel is weakly weighted and the appropriate weighting value is set, so that the significant deterioration does not occur. The peak-to-average ratio index is a criterion. Generally, the appropriate weighting factor can also be determined by simulation, so as to improve the demodulation stability of the MAC channel after peak clipping, which is the time-division weighted peak clipping device of the embodiment applied to CDMA. The core idea of the system's EV-DO signal. 6 is a frame structure diagram of a forward signal of a TD-SCDMA system, and the baseband transmission power of the TS0 time slot, the DWPTS, and the GP time slot of the TD-SCDMA signal shown in FIG. 6 is different from the service time slot power, and the current system is used for cutting The peak threshold is a peak clipping threshold set according to the rated power of the system. In this case, the power loss caused by the peak clipping will be affected, which will affect the terminal access. For this case, we can follow this article. The method performs peak clipping processing by weighting the offset pulses by time slots, and assigns a weighting factor of less than 1 to the peak cancellation pulses of the three time slots, so as to avoid serious energy loss caused by peak clipping. The problem. The weighting process of this embodiment is as follows: The weighting control signal generating module 12 constructs a weighting factor control signal according to a frame synchronization signal or a modulation mode reference signal that is improved by the system; setting a segmentation weighting factor value to define an appropriate weighting factor; and a peak pulse weighting module 14 The currently extracted peak pulse is weighted. With the peak clipping device of the embodiment, it is no longer necessary to compromise the system index for the different modulation modes or some special time slots during the intermediate frequency peak clipping, and the peak clipping can be performed for the dynamic characteristics of the signal real-time variation. The optimization of performance indicators enables them to achieve better performance in a variety of application scenarios and to ensure system performance optimization. Embodiment 2 As shown in FIG. 4, the weighting control signal generating module 12 and the peak pulse weighting module 14 are two functional modules added in a conventional peak clipping module. Wherein, the peak pulse weighting module 14, as shown in FIG. 7, includes a The weighting factor gating unit and the weighting unit 140 are based on the weighting control signal generated by the weighting control signal generating module 12 to perform time-division output selection on the input plurality of weighting factors, and the weighting unit 142 is A multiplier unit consists of weighting the crest factor. The weighted control signal generating module 12 generates a time-divisionally weighted control signal according to the modulation reference signal or the frame synchronization reference signal given by the system, and the signal may be two or more states corresponding to two or more different weighting factors. Generally, the modulation reference signal can use a frame synchronization signal or a PP2S signal. Here, taking the EV-DO signal processing of the CDMA system as an example, it is only necessary to distinguish the peaks of the MAC channel from the non-MAC channel, and perform weighting processing of the peak pulses separately. Therefore, only two states need to be considered here, corresponding to two weighting factors. The corresponding timing relationship between the weighting factor and the weighted control signal is as shown in FIG. 8. Here, the modulation reference signal is a PP2S reference signal provided by the CDMA system, and only needs to be specially weighted for the MAC channel, so the weighted control signal only needs to be Two states are generated, corresponding to two weighting factor parameter values. Usually the weighting factor alpha in Figure 7 is an interface parameter that can be set by software. At present, the conventional peak clipping devices are composed of multi-stage cascaded peak clipping modules. The weight factor setting in the device of the utility model can be separately set for each peak clipping module, and the time sharing weighting factors of each level of peak clipping are set to be different. The value, usually to ensure that the signal peak-to-average ratio is not affected too much, will set the weighting factor of the previous stage peak clipping module to a lower value, and the latter stage can select a weighting factor slightly closer to 1, so that both solutions can be achieved. While the indicator is improved, the peak-to-average ratio indicator will not be excessively deteriorated. The peak clipping device of this embodiment is suitable for use in LTE, GSM, and TD-SCDMA systems. The peak clipping device of the embodiment can set the peak clipping parameter for different time slot signal powers or different modulation modes, and can also set a user-defined timing according to the signal variation characteristics to set the peak clipping weighting parameter, thereby achieving Optimize the purpose of peak clipping performance. The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A peak clipping device, comprising: a peak pulse generation module, a weighted control signal generation module, a peak pulse weighting module, and a first adder module, wherein

The peak pulse generating module is connected to the peak pulse weighting module, configured to generate a peak pulse signal according to the input signal and send the peak pulse weighting module to the peak pulse weighting module;

The weighting control signal generating module is connected to the peak pulse weighting module, and configured to generate a weighting factor control signal according to the acquired modulation mode reference signal or frame synchronization signal and send the signal to the peak value weighting module;

The peak pulse weighting module is connected to the first adder module, and is configured to perform weighting processing on the peak pulse signals received in different time segments according to the received weighting factor control signal, and weighting the processed a peak pulse signal is sent to the first adder module;

The first adder module is configured to superimpose the weighted processed peak pulse signal on the peak to be peaked signal, and cancel the peak signal to be clipped.

2. The apparatus according to claim 1, wherein the peak pulse weighting module comprises:

a weighting factor strobing unit is connected to the weighting control signal generating module, and configured to output the plurality of weighting factors to the weighting unit according to the weighting factor control signal generated by the weighting control signal generating module;

The weighting unit is connected to the weighting factor gating unit, and is configured to perform weighting processing on the peak pulse signals received in different time periods according to a weighting factor output by the weighting factor gating unit, and weighting The processed peak pulse signal is superimposed on the peak to be peaked signal, and the peak signal to be clipped is cancelled.

3. The apparatus according to claim 2, wherein the weighting unit is a multiplier.

4. The device according to claim 1, further comprising:

a filter, connected between the peak pulse weighting module and the first adder module, configured to filter a peak pulse signal subjected to weighting by the peak pulse weighting module, and filter the peak pulse signal Sended to the first adder module. The device according to claim 1, further comprising: a peak search module, connected to the second adder module, configured to send an input signal greater than a preset threshold to the second adder module;

a first delay module, connected to the second adder module, configured to delay processing the input signal, and send the delayed input signal to the second adder module;

The second adder module is configured to superimpose the received input signal from the peak search module and the received delayed input signal from the first delay module to generate the peak signal, And transmitting the peak signal to the peak pulse generating module.

6. The device according to claim 5, further comprising:

a second delay module, connected to the peak search module, configured to delay processing an input signal from the peak search module that is greater than a preset threshold to generate the peak to be peaked signal, and to A peak signal is sent to the first adder module.

A mobile communication system comprising: the apparatus of any one of claims 1 to 6.